JP2023179591A - Method and apparatus for intra sub-partition coding mode - Google Patents

Abstract

To provide an apparatus and a method for an Intra Sub-Partition (ISP).SOLUTION: The method includes steps of: obtaining information of ISP; and determining a size of a chroma transform block (TB) of a coding unit on the basis of SubWidthC and SubHeightC when at least first condition is fulfilled. The first condition includes information of the ISP indicating that the ISP is used for splitting a luma coding block. SubWidthC and SubHeightC are variables depending on chroma format information. The chroma format information indicates a chroma format of a picture to which the coding unit is belonged. The method can be applied to all the chroma format, and the chroma format includes at least one of 4:2:0, 4:2:2, and 4:4:4.SELECTED DRAWING: Figure 9

Description

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TECHNICAL FIELD Implementations of the present disclosure relate generally to the field of picture processing, and more specifically to sub-partition (ISP) coding modes.

Video coding (video encoding and decoding) is used in a wide range of digital video applications, such as broadcast digital TV, video transmission over the Internet and mobile networks, real-time conversation applications such as video chat, video conferencing, etc. used in camcorders, DVD and Blu-ray discs, video content capture and editing systems, and security applications.

The amount of video data required to depict even a relatively short video can be substantial, and the data is streamed over communication networks with limited bandwidth capacity. or otherwise communicated, difficulties may arise. Therefore, video data is typically compressed before being communicated over today's telecommunications networks. The size of the video may also be an issue, as memory resources may be limited if the video is stored on a storage device. Video compression devices often use software and/or hardware at the source to encode video data before transmission or storage, thereby reducing the amount of data needed to represent a digital video image. let The compressed data is then received at the destination by a video decompression device that decodes the video data. With limited network resources and the ever-increasing demand for higher video quality, improved compression and decompression techniques are desired that improve compression ratios with little sacrifice in image quality.

Intra-subpartition (ISP) coding mode is an updated version of line-based intra-prediction (LIP) coding. ISP techniques perform sub-partitioning only on luma blocks, and for chroma blocks, prediction and further transformations are performed on the entire coding unit without partitioning. The objective is to provide an accurate and versatile method for determining the size of a chroma transform block (TB) of a coding unit for ISP.

Embodiments of the present application provide an apparatus and a method for encoding and decoding according to the independent claims.

These and other objects are achieved by the subject matter of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the drawing.

According to a first aspect, the invention relates to a method performed by a decoding device. The method includes: obtaining intra sub-partition (ISP) information, the ISP information indicating whether the ISP is used to partition a luma coding block of the coding unit; and determining a size of a chroma transform block (TB) of the coding unit based on SubWidthC and SubHeightC if at least the first condition is satisfied. SubWidthC and SubHeightC are variables that depend on chroma format information. The chroma format information indicates the chroma format of the picture to which the coding unit belongs, and the chroma format is at least one of 4:2:0, 4:2:2, or 4:4:4. including. The first condition is: 1) a single tree is used to partition the coding unit, and 2) the ISP information indicates that the ISP is used to partition the luma coding blocks. Including what is shown.

According to a second aspect, the invention relates to a method performed by an encoding device. The method includes: determining a size of a chroma transform block of a coding unit based on SubWidthC and SubHeightC if at least a first condition is satisfied. SubWidthC and SubHeightC are variables that depend on chroma format information. The chroma format information indicates the chroma format of the picture to which the coding unit belongs, and the chroma format is at least one of 4:2:0, 4:2:2, or 4:4:4. including. The first condition includes: 1) a single tree is used to partition the coding unit, and 2) an ISP is used to partition the luma coding blocks of the coding unit. . The method further includes encoding the bitstream, the bitstream including information indicating that an ISP is used to partition luma coding blocks of the coding unit.

The method according to the first aspect of the invention can be performed by a decoding device according to the third aspect of the invention. The device 1100 includes an acquisition unit 1101 and a determination unit 1102. The acquisition unit 1101 is configured to acquire ISP information, where the ISP information indicates whether the ISP is used to divide the luma coding blocks of the coding unit. The determining unit 1102 is configured to determine the size of a chroma transform block (TB) of the coding unit based on SubWidthC and SubHeightC, where SubWidthC and SubHeightC are chroma This is a variable that depends on format information. The chroma format information indicates the chroma format of the picture to which the coding unit belongs, and the chroma format is at least one of 4:2:0, 4:2:2, or 4:4:4. including. The first condition is: 1) a single tree is used to partition the coding unit, and 2) the ISP information indicates that the ISP is used to partition the luma coding blocks. Including what is shown. Further features and forms of implementation of the method according to the third aspect of the invention correspond to features and forms of implementation of the apparatus according to the first aspect of the invention.

The method according to the second aspect of the invention can be performed by an encoding device according to the fourth aspect of the invention. Apparatus 1200 includes a determining unit 1201 and an encoding unit 1202. The determining unit 1201 is configured to determine the size of the chroma transform block of the coding unit based on SubWidthC and SubHeightC if at least the first condition is fulfilled. SubWidthC and SubHeightC are two variables that depend on chroma format information. The chroma format information indicates the chroma format of the picture to which the coding unit belongs, and the chroma format is at least one of 4:2:0, 4:2:2, or 4:4:4. including. The first condition includes: 1) a single tree is used to partition the coding unit, and 2) an ISP is used to partition the luma coding blocks of the coding unit. . Encoding unit 1202 is configured to encode a bitstream, where the bitstream includes information indicating that an ISP is used to partition luma coding blocks of the coding unit.

Further features and forms of implementation of the method according to the fourth aspect of the invention correspond to features and forms of implementation of the apparatus according to the second aspect of the invention.

According to a fifth aspect, the invention relates to an apparatus for decoding a video stream, including a processor and a memory. The memory stores instructions that cause the processor to perform the method according to the first aspect.

According to a sixth aspect, the invention relates to an apparatus for encoding a video stream, including a processor and a memory. The memory stores instructions that cause the processor to perform the method according to the second aspect.

According to a seventh aspect, a computer readable storage medium is proposed having instructions stored thereon that, when executed, cause one or more processors to be configured to code video data. The instructions cause one or more processors to perform a method according to the first aspect or the second aspect or any possible embodiment of the first aspect or the second aspect.

According to an eighth aspect, the invention provides a program code for carrying out the method according to the first or second aspect or any possible embodiment of the first or second aspect when executed on a computer. Relates to computer programs containing. Embodiments of the invention apply to all chroma formats. The chroma format includes at least one of 4:2:0, or 4:2:2, or 4:4:4. An accurate and versatile method for determining the size of chroma transform blocks for ISP is achieved. The details of one or more embodiments are set forth in the accompanying drawings and the specification below. Other features, objects, and advantages will be apparent from the description, drawings, and claims.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings and drawings.
FIG. 1 is a block diagram illustrating an example of a video coding system configured to implement embodiments of the present invention. 1 is a block diagram illustrating another example of a video coding system configured to implement embodiments of the present invention. FIG. 1 is a block diagram illustrating an example of a video encoder configured to implement embodiments of the present invention. FIG. 1 is a block diagram illustrating an exemplary structure of a video decoder configured to implement embodiments of the present invention. FIG. FIG. 1 is a block diagram showing an example of an encoding device or a decoding device. FIG. 2 is a block diagram showing another example of an encoding device or a decoding device. The nominal vertical and horizontal position of the 4:2:0 luma and chroma samples in the picture. The nominal vertical and horizontal position of the 4:2:2 luma and chroma samples in the picture. The nominal vertical and horizontal position of 4:4:4 luma and chroma samples in a picture. 1 shows an embodiment of an ISP coding method performed by a decoding device according to the invention; 1 shows an embodiment of an ISP coding method performed by a coding device according to the invention; 1 illustrates an embodiment of a decoding device according to the present invention. 1 illustrates an embodiment of an encoding device according to the present invention. FIG. 3 is a block diagram showing a configuration example of a content supply system 3100 that implements a content distribution service. FIG. 2 is a block diagram showing the configuration of an example of a terminal device.

In the following, identical reference symbols refer to identical or at least functionally equivalent features, unless explicitly stated otherwise.

In the following description, reference is made to the accompanying drawings, which form a part of the present disclosure, and which illustrate, by way of example, certain aspects of embodiments of the invention or in which embodiments of the invention may be used. . It is understood that embodiments of the invention may be used in other ways and may include structural or logical changes not shown in the accompanying drawings. Therefore, the following detailed description should not be construed in a limiting sense, with the scope of the invention being defined by the appended claims.

For example, it is understood that disclosures related to the described methods may also apply to corresponding devices or systems configured to perform the methods, and vice versa. For example, if one or more particular method steps are described, the corresponding device may include one or more units, such as functional units (e.g., one a unit that performs the above steps, or multiple units that each perform one or more of the steps), even if such unit or units are not explicitly shown or described in the drawings. Even if it is not, it may still be included. On the other hand, if a particular device is described on the basis of one or more units, e.g. a step for performing a function of one or more units, or multiple steps each performing a function of one or more of a plurality of units), even if such one or more steps are may be included even if not explicitly shown or described. Furthermore, it is understood that the features of the various exemplary embodiments and/or aspects described herein may be combined with each other, unless stated otherwise.

Video coding typically refers to the processing of a sequence of pictures to form a video or a video sequence. In the field of video coding, instead of the term "picture", the term "frame" or "image" may be used synonymously. Video coding (or coding in general) includes two parts: video encoding or video decoding. Video encoding is performed at the source and typically encodes the original video picture (for more efficient storage and/or transmission) to reduce the amount of data needed to represent the video picture. (e.g., by compression). Video decoding is performed at the destination and typically involves inverse processing compared to the encoder to reconstruct the video picture. Embodiments for "coding" of video pictures (or pictures in general) shall be understood as relating to "encoding" or "decoding" of video pictures or individual video sequences. do. The combination of encoding part and decoding part is also referred to as CODEC (Coding and Decoding).

In case of lossless video coding, it is possible to reconstruct the original video picture, i.e. the reconstructed video picture has the same quality as the original video picture (during storage and transmission , no transmission loss or other data loss). In the case of non-lossless video coding, further compression is performed, for example by quantization, to reduce the amount of data representing the video picture, and the video picture cannot be completely reconstructed at the decoder side. That is, the quality of the reconstructed video picture is lower or worse than the quality of the original video picture.

Some video coding standards belong to the group of "non-lossless hybrid video codexes" (i.e. 2D codecs for applying spatial and temporal prediction in the sample domain and quantization in the transform domain). (combined with transform coding). Each picture of a video sequence is typically partitioned into a set of non-overlapping blocks, and coding is typically performed at the block level. In other words, on the encoder side, the video is generated using e.g. spatial (intra-picture) prediction and temporal (inter-picture) prediction to generate predictive blocks, the current block (current processed/to-be-processed block) ) by subtracting the prediction block from the vector to obtain a residual block, transforming the residual block, and quantizing the residual block in the transform domain to reduce the amount of data to be transmitted (compression). Typically processed, i.e. encoded, at the block (video block) level, and at the decoder side, inverse processing compared to the encoder is partially applied to the encoded or compressed block to improve the representation. To reconfigure the current block. Furthermore, the encoder repeats the processing loop of the decoder, so that both may produce the same prediction (e.g., intra and inter prediction) and/or reconstruction in order to process or code subsequent blocks. Dew.

Hereinafter, embodiments of a video coding system 10, a video encoder 20, and a video decoder 30 will be described based on FIGS. 1-3.

FIG. 1A is a schematic block diagram illustrating an example coding system 10, such as a video coding system 10 (or coding system 10 for short) that can employ the techniques of the present application. Video encoder 20 (or encoder 20 for short) and video decoder 30 (or decoder 30 for short) of video coding system 10 are configured to perform techniques according to various examples described herein. Represents an example of a possible device.

As shown in FIG. 1A, coding system 10 includes a source device configured to provide encoded picture data 21 to a destination device 14 that decodes the encoded picture data 21 , for example. Contains 12.

Source device 12 includes an encoder 20 and additionally, or optionally, a picture source 16, a preprocessor (or preprocessing unit) 18, such as a picture preprocessing unit 18, and a communication interface or May contain unit 22.

Picture source 16 may be any type of picture capture device, such as a camera that captures real-world pictures, and/or any type of picture capture device, such as a computer graphics processor that produces computer animation pictures. any type of picture-generating device, or real-world pictures, computer-generated pictures (e.g., screen content or virtual reality (VR) pictures), and/or any combination thereof (e.g., augmented reality (AR) pictures). It may also include or be any other type of obtaining and/or providing device. A picture source can be any type of memory or storage that stores any of the pictures mentioned above.

In distinction from preprocessing unit 18 and the processing performed by preprocessing unit 18, pictures and picture data 17 may also be referred to as unprocessed pictures or unprocessed picture data 17.

Preprocessing unit 18 is configured to receive (unprocessed) picture data 17 and perform preprocessing on picture data 17 to obtain preprocessed pictures 19 or preprocessed picture data 19. It is configured. Pre-processing performed by pre-processing unit 18 may include, for example, cropping, color format conversion (eg, RGB to YCbCr), color correction, or noise reduction. It can be appreciated that pre-processing unit 18 may be an optional component.

The video encoder 20 is configured to receive preprocessed picture data 19 and provide encoded picture data 21 (further details may be explained, for example, based on FIG. 2 below). ).
A communications interface 22 of source device 12 receives encoded picture data 21 and transmits encoded picture data 21 (or any further processed version thereof) to other sources via communications channel 13. It may be configured to transmit to a device, such as destination device 14 or any other device, for storage or direct reconfiguration.

Destination device 14 includes a decoder 30 (e.g., video decoder 30) and additionally or optionally includes a communication interface or unit 28, a post-processing processor 32 (or post-processing unit 32), and a display device 34. May include.

The communication interface 28 of the destination device 14 transmits encoded picture data 21 (or any further processed versions thereof), e.g., directly from the source device 12 or from any other source, e.g. - configured to receive from a device, for example a storage device for encoded picture data, and provide encoded picture data 21 to the decoder 30;

Communication interface 22 and communication interface 28 may be connected via a direct communication link, such as a direct wired or wireless connection, between source device 12 and destination device 14, or via any type of network, such as wired or wireless. transmitting or transmitting encoded picture data 21 or encoded data over a network or any combination thereof, or over any type of private and public network or any combination thereof; can be configured to receive.

The communication interface 22 may, for example, package the encoded picture data 21 into a suitable format, such as a packet, and/or any type of transmission code for transmission over a communication link or network. The encoded picture data can be configured to process encoded picture data using encoding or processing.

A communication interface 28 forming a corresponding part of the communication interface 22 may, for example, receive transmitted data and carry out any kind of corresponding transmission decoding or processing and/or processing in order to obtain encoded picture data 21. Alternatively, it may be configured to process the transmitted data using unpackaging.

Both communication interface 22 and communication interface 28 can be configured as a one-way communication interface, as indicated by the arrows for communication channel 13 from source device 12 to destination device 14 in FIG. 1A, or as a two-way communication interface. and confirming and exchanging communication links and/or any other information related to data transmissions, e.g. encoded picture data transmissions, e.g. to send and receive messages, e.g. to set up connections, etc. It can be configured as follows.

The decoder 30 is configured to receive encoded picture data 21 and provide decoded picture data 31 or decoded pictures 31 (further details can be found, for example, in FIG. 5 and will be explained below).

A post-processing processor 32 of the destination device 14 post-processes decoded picture data 31 (also referred to as reconstructed picture data), such as decoded pictures 31, to produce post-processed pictures. 33 is configured to obtain post-processed picture data 33 such as 33. Post-processing performed by post-processing unit 32 may include, for example, color format conversion (e.g., YCbCr to RGB), color correction, cropping, resampling, or any other processing, such as for display by display device 34. For example, it may include things for preparing decoded picture data 31, etc.

Display device 34 of destination device 14 is configured to receive post-processed picture data 33 and display the picture, eg, to a user or viewer. Display device 34 may be or include any type of display that represents the reconstructed picture, such as an integrated or external display or monitor. The display may be, for example, a liquid crystal display (LCD), an organic light emitting diode (OLED) display, a plasma display, a projector, a micro-LED display, a liquid crystal on silicon (LCoS), a digital light processor (DLP), or any other type. may include a display.

Although FIG. 1A depicts source device 12 and destination device 14 as separate devices, device embodiments may also include the functionality of both or both, source device 12 or corresponding functionality and destination device 14 or This may include the ability to: In such embodiments, the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality may be configured using the same hardware and/or software, or using separate hardware and/or software. It may be realized by any combination of the following.

As will be clear to a person skilled in the art based on the description, the presence and (strict) division of the functions or functions of the various units in the source device 12 and/or destination device 14 shown in FIG. and may vary depending on the application.

Encoder 20 (e.g., video encoder 20) or decoder 30 (e.g., video decoder 30) or both encoder 20 and decoder 30 may be implemented by processing circuitry such as that shown in FIG. 1B, e.g., one or more microprocessors. , digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, hardware, dedicated to video coding, or any combination thereof. Is possible. Encoder 20 may be implemented with processing circuitry 46 to embody the various modules described with respect to encoder 20 of FIG. 2 and/or any other encoder system or subsystem described herein. . Decoder 30 may be implemented with processing circuitry 46 to embody the various modules described with respect to decoder 30 of FIG. 3 and/or any other decoder system or subsystem described herein. . The processing circuitry may be configured to perform various operations as described below. If the techniques are partially implemented in software, as shown in FIG. 5, the device stores software instructions on a suitable non-transitory computer-readable storage medium for performing the techniques of the present disclosure. instructions can be executed in hardware using one or more processors. Either video encoder 20 and video decoder 30 may be integrated as part of a combined encoder/decoder (CODEC) within a single device, as shown in FIG. 1B, for example.

The source device 12 and the destination device 14 can be any of a wide range of devices, including any type of handheld or stationary device, such as a notebook or laptop computer, a mobile phone, a smart phone, a tablet or tablet computer, a camera, etc. , desktop computers, set top boxes, televisions, display devices, digital media players, video game consoles, video streaming devices (such as content service servers or content distribution servers), broadcast receiving devices, It may include a broadcast transmission device, etc., and may or may not use any type of operating system. In some cases, source device 12 and destination device 14 may be equipped for wireless communication. Accordingly, source device 12 and destination device 14 may be wireless communication devices.

In some cases, the video coding system 10 shown in FIG. 1A is just one example, and the techniques of the present application may be useful for video coding setups that do not necessarily involve any data communication between encoding and decoding devices. (e.g. video encoding or video decoding). In other examples, data is retrieved from local memory, streamed over a network, etc. A video encoding device can encode and store data in memory, and/or a video decoding device can retrieve data from memory and decode it. In some examples, encoding and decoding are performed by devices that do not communicate with each other, but only encode data into and/or retrieve and decode data from memory.

For convenience of explanation, embodiments of the invention may be applied to, for example, High Efficiency Video Coding (HEVC) or General Purpose Video Coding (VVC), ITU-T Video Coding Expert Group (VCEG) and ISO/IEC Video Expert Group. This application is described by reference to the next generation video coding standard reference software developed by the Joint Research Team on Video Coding (MPEG) (JCT-VC). Those skilled in the art will understand that embodiments of the invention are not limited to HEVC or VVC.

Encoder and Encoding Method FIG. 2 is a schematic block diagram of an exemplary video encoder 20 configured to implement the present techniques. In the example of FIG. 2, the video encoder 20 includes an input 102 (or input interface 201), a residual calculation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, and an inverse transform. A processing unit 212, a reconstruction unit 214, a loop filter unit 220, a decoded picture buffer (DPB) 230, a mode selection unit 260, an entropy encoding unit 270, an output 272 (or interface 272). Mode selection unit 260 may include inter prediction unit 244, intra prediction unit 254, and partitioning unit 262. Inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). Video encoder 20 shown in FIG. 2 may also be referred to as a hybrid video encoder or a video encoder with a hybrid video codec.

Residual calculation unit 204, transform processing unit 206, quantization unit 208, mode selection unit 260 may be referred to as forming the forward signal path of encoder 20, inverse quantization unit 210, inverse transform processing Unit 212, reconstruction unit 214, buffer 216, loop filter 220, decoded picture buffer (DPB) 230, inter prediction unit 244, and intra prediction unit 254 provide the reverse signal path of video encoder 20. The reverse signal path of video encoder 20 corresponds to the signal path of a decoder (see video decoder 30 in FIG. 3). In addition, the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the loop filter 220, the decoded picture buffer (DPB) 230, the inter prediction unit 244, and the intra prediction unit 254 It is also referred to as forming the "built-in decoder" of encoder 20.

Picture & Picture Partitioning (Picture & Block)
Encoder 20 may be configured to receive, for example via input 202, pictures 17 (or picture data 17), for example pictures of a video or a sequence of pictures forming a video sequence. The received pictures or picture data may also be referred to as preprocessed pictures 19 (or preprocessed picture data 19). For simplicity, the following description will refer to picture 17. Picture 17 may also be referred to as the current picture or the picture to be coded (particularly in video coding, where the current picture is removed from another picture, e.g. from the same video sequence, i.e. a video that also contains the current picture). - distinguish from previously encoded and/or decoded pictures of the sequence).

A (digital) picture is, or can be thought of as, a two-dimensional array or matrix of samples with intensity values. The samples in an array may also be referred to as pixels (short for picture elements) or pels. The number of samples in the horizontal and vertical directions (or axes) of an array or picture defines the size and/or resolution of the picture. Three color components are typically used for color representation, ie a picture may be represented by or include three sample arrays. In RGB format or color space, a picture includes corresponding arrays of red, green, and blue samples. However, in video coding, each sample is typically represented in a luminance/chrominance format or color space, e.g. YCbCr, where YCbCr is the luminance component denoted Y (sometimes L is also used instead). ) and two chrominance components denoted by Cb and Cr. The luminance (or luma) component Y represents the brightness or gray level intensity (as in a gray scale picture, for example), and the two chrominance (or chroma) components Cb and Cr represent the chrominance or color Represents information components. Thus, a picture in YCbCr format includes a luminance sample array of luminance sample values (Y) and two chrominance sample arrays of chrominance values (Cb and Cr). Pictures in RGB format can be converted or converted to YCbCr format and vice versa, the process also known as color conversion or conversion. If the picture is monochrome, the picture may contain only a luminance sample array. Thus, a picture can be, for example, an array of luma samples in monochrome format, or an array of luma samples and two corresponding arrays of chroma samples 4:2:0, 4:2:2, and 4: May be in 4:4 color format.

Embodiments of video encoder 20 include a picture partitioning unit (not shown in FIG. 2) configured to partition picture 17 into multiple (typically non-overlapping) picture blocks 203. ) may be included. These blocks are also referred to as root blocks, macro blocks (H.264/AVC) or coding tree blocks (CTB) or coding tree units (CTU) (H.265/HEVC and VVC). In some cases. The picture partitioning unit is configured to partition pictures, subsets, or groups of pictures so as to use the same block size and a corresponding grid defining the block size for all pictures of a video sequence. The blocks can be configured to change the block size between and partition each picture into a corresponding block.

In further embodiments, the video encoder may be configured to directly receive blocks 203 of picture 17, eg one, some or all blocks forming picture 17. Picture block 203 may also be referred to as a current picture block or a picture block to be coded.

Similar to picture 17, block 203 is, or can be thought of as, a two-dimensional array or matrix of samples with intensity values (sample values), again with smaller dimensions than picture 17. . In other words, block 203 may, for example, contain one sample array (e.g. a luma array in the case of a monochrome picture, or a luma or chroma array in the case of a color picture) or three sample arrays (e.g. luma and two chroma arrays in the case of a color picture 17), or any other quantity and/or type of array depending on the color format applied. The number of horizontal and vertical (or axial) samples of block 203 defines the size of block 203. Thus, a block may be, for example, an MxN (M columns and N rows) array of samples, or an MxN array of transform coefficients.

As shown in FIG. 2, the encoder 20 is configured to encode the blocks of the picture 17 block by block; for example, encoding and prediction are performed block by block 203.

The embodiment of video encoder 20 shown in FIG. 2 can be further configured to partition and/or encode pictures by using slices (also referred to as video slices), can be partitioned into or encoded using one or more slices (typically non-overlapping), each slice containing one or more blocks (e.g., CTU ) can be included.

The embodiment of video encoder 20 shown in FIG. 2 partitions and/or encodes pictures by using tile groups (also referred to as video tile groups) and/or tiles (also referred to as video tiles). The picture can be partitioned into or encoded using one or more tile groups (typically non-overlapping). , each tile group may include, for example, one or more blocks (e.g., CTUs) or one or more tiles, and each tile may be, for example, rectangular in shape, with one It may include more than one block (eg, CTU), eg, a complete or fragmented block.

Residual Calculation The residual calculation unit 204 calculates the picture block 203 and the prediction block 265 (prediction further details about block 265 below) to obtain residual block 205 in the sample domain. It is.

Transform The transform processing unit 206 is configured to apply a transform, e.g. a discrete cosine transform (DCT) or a discrete sine transform (DST), on the sample values of the residual block 205 to obtain transform coefficients 207 in the transform domain. Is possible. Transform coefficients 207 are also referred to as transform residual coefficients and may represent residual blocks 205 in the transform domain.

Transform processing unit 206 may be configured to apply an integer approximation of DCT/DST, such as the transform specified for HEVC/H.265. Compared to orthogonal DCT transforms, such integer approximations are typically scaled by some factor. To ensure the norm of the residual blocks processed by the forward and inverse transforms, additional scaling factors are applied as part of the transform process. The scaling factor is typically selected based on certain constraints such as a scaling factor that is a power of 2 for shift operations, bit depth of the transform coefficients, trade-off between accuracy and implementation cost, etc. be done. A particular scaling factor is specified for the inverse transform, e.g. by inverse transform processing unit 212 (and the corresponding inverse transform by inverse transform processing unit 312, e.g. in video decoder 30), and for the forward transform, e.g. by transform processing unit 206 in encoder 20. The corresponding scaling factor for may be specified accordingly.

Embodiments of the video encoder 20 (individual transform processing units 206) may output transform parameters, such as a type of transform or transforms, either directly or encoded or compressed by an entropy encoding unit 270. , so that video decoder 30 can receive and use the transformation parameters for decoding.

Quantization The quantization unit 208 can be configured to quantize the transform coefficients 207 and obtain quantized coefficients 209, for example by applying scalar quantization or vector quantization. Quantized coefficients 209 may also be referred to as quantized transform coefficients 209 or quantized residual coefficients 209.

The quantization process may reduce the bit depth associated with all or some of the transform coefficients 207. For example, an n-bit transform coefficient may be rounded to an m-bit transform coefficient during quantization, where n is greater than m. The degree of quantization can be modified by adjusting the quantization parameter (QP). For example, for scalar quantization, different scaling may be applied to achieve finer or coarser quantization. Smaller quantization steps correspond to finer quantization, and larger quantization steps correspond to coarser quantization. The applicable quantization step size may be indicated by a quantization parameter (QP). For example, the quantization parameter may be an index to a predetermined set of applicable quantization step sizes. For example, a small quantization parameter can correspond to fine quantization (small quantization step size), and a large quantization parameter can correspond to coarse quantization (large quantization step size). Yes, and vice versa. Quantization may involve division by the quantization step size, and corresponding and/or inverse quantization, such as by inverse quantization unit 210, may involve multiplication by the quantization step size. . Embodiments according to some standards, such as HEVC, may be configured to use quantization parameters to determine the quantization step size. In general, the quantization step size can be calculated based on the quantization parameter using a fixed-point approximation of the equation involving division. An additional scaling factor is introduced for quantization and dequantization, which is the norm of the residual block due to the scaling used in the fixed-point approximation of the equations for the quantization step size and quantization parameters. It is possible to restore the norm, which may be modified by In one example implementation, inverse transform and inverse quantization scaling may be combined. Alternatively, a customized quantization table may be used and signaled from the encoder to the decoder, eg in the bitstream. Quantization is a non-lossless operation, and loss increases as the quantization step size increases.

Embodiments of video encoder 20 (respective quantization unit 208) may be configured to output a quantization parameter (QP), for example encoded directly or by entropy encoding unit 270. , so that video decoder 30 can receive and apply the quantization parameters for decoding.

Inverse Quantization The inverse quantization unit 210 applies the inverse quantization of the quantization unit 208 to the quantized coefficients, e.g. The inverse quantization coefficients 211 are configured to be obtained by applying the quantization step based on or using the quantization step. Inverse quantized coefficients 211 may also be referred to as inverse quantized residual coefficients 211, and correspond to transform coefficients 207, but due to losses due to quantization, they typically do not match the transform coefficients.

Inverse Transform The inverse transform processing unit 212 applies an inverse transform of the transform applied by the transform processing unit 206, such as an inverse discrete cosine transform (DCT) or an inverse discrete sine transform (DST) or other inverse transform, to transform the sample. configured to obtain a reconstructed residual block 213 (corresponding dequantized coefficients 213) in the domain. Reconstructed residual block 213 may also be referred to as transform block 213.

Reconstruction The reconstruction unit 214 (e.g., adder or summation unit 214) adds the transform block 213 (i.e., the reconstructed residual block 213) to the prediction block 265 to obtain, e.g., the reconstructed residual block. The reconstructed block 215 in the sample domain is configured to be obtained by adding the sample values of 213 and the sample values of the prediction block 265 sample by sample.

Filtering A loop filter unit 220 (or "loop filter" 220 for short) filters the reconstructed block 215 to obtain a filtered block 221, or in general, a filtered block 221. The reconstructed sample is configured to be filtered to obtain the sample. The loop filter unit is configured, for example, to smooth pixel transitions or otherwise improve video quality. Loop filter unit 220 includes one or more loop filters, such as a deblocking filter, a sample adaptive offset (SAO) filter, or one or more other filters, such as bilateral filters, adaptive offset filters, etc. It may include a loop filter (ALF), a sharpening or smoothing filter, or a collaborative filter, or any combination thereof. Although loop filter unit 220 is shown in FIG. 2 as being an in-loop filter, in other configurations loop filter unit 220 may be implemented as a post-loop filter. Filtered block 221 may also be referred to as filtered reconstructed block 221.

Embodiments of video encoder 20 (respective loop filter units 220) encode loop filter parameters (such as sample adaptive offset information), e.g. directly or by entropy decoding unit 270. For example, the decoder 30 can receive and apply the same or respective loop filter parameters for decoding.

Decoded Picture Buffer Decoded picture buffer (DPB) 230 stores reference pictures, or generally reference picture data, for use in encoding video data by video encoder 20. It may be a memory. The DPB230 can be used with various memory devices such as dynamic random access memory (DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. It may be formed by any one of the following. A decoded picture buffer (DPB) may be configured to store one or more filtered blocks 221. The decoded picture buffer 230 may also contain other previously stored pictures, such as the same current picture or a different picture, such as a previously reconstructed picture, such as a previously reconstructed and filtered block 221. The filtered block may be configured to store a completely previously reconstructed, i.e. decoded, picture (and corresponding reference block and corresponding sample) and/or e.g. inter-prediction. It is possible to provide a partially reconstructed current picture (and corresponding reference blocks and corresponding samples) for.
The decoded picture buffer (DPB) 230 also contains one or more unfiltered reconstructed blocks 215, or typically the reconstructed blocks 215 have been filtered by the loop filter unit 220, for example. If not, it may be configured to store the unfiltered reconstructed samples, or any other further processed versions of the reconstructed blocks or samples.

Mode selection (partitioning & prediction)
Mode selection unit 260 includes a partitioning unit 262, an inter prediction unit 244, and an intra prediction unit 254, and includes original picture data, e.g., original block 203 (current block 203 of current picture 17), and Reconstructed picture data, e.g. from the same (current) picture and/or from one or more previously decoded pictures, e.g. , a line buffer (not shown)). The reconstructed picture data is used as reference picture data for prediction, e.g. inter-prediction or intra-prediction, to obtain prediction blocks 265 or predictors 265.

The mode selection unit 260 determines or selects the prediction mode (not including partitioning) of the current block and the partitioning for the prediction mode (e.g., intra or inter prediction mode), calculates the residual block 205 and reconstructs the block 215. The prediction block 265 may be configured to generate a corresponding prediction block 265 that is used for the reconstruction of the prediction block 265.

Embodiments of the mode selection unit 260 select the best match, or in other words, the lowest residual (minimum residual means better compression for transmission or storage), or the lowest signaling overhead (minimum Signaling overhead means better compression for transmission or storage) or consider or balance both partitioning and prediction modes (e.g., those supported by mode selection unit 260 or available can be configured to select from The mode selection unit 260 may be configured to determine the partitioning and prediction mode based on rate-distortion optimization (RDO), ie to select the prediction mode that provides the minimum rate-distortion. Terms such as "best", "worst", "optimal", etc. in this context do not necessarily refer to the overall "best", "worst", "optimal", etc., but rather if a value exceeds a threshold or It may also refer to the fulfillment of termination or selection criteria such as below, or other constraints that may result in a "suboptimal selection" but reduce complexity and processing time.

In other words, the partitioning unit 262 may use, for example, quadtree partitioning (QT), binary partitioning (BT) or tertiary tree partitioning (TT) or any combination thereof. , block 203 may be configured to partition the block 203 into smaller block partitions or sub-blocks (which again form blocks) and perform prediction on each of the block partitions or sub-blocks, for example. , the mode selection includes the selection of a tree structure of partitioned blocks 203, and a prediction mode is applied to each of the block partitions or sub-blocks.

Partitioning (eg, by partitioning unit 260) and prediction processing (eg, by inter-prediction unit 244 and intra-prediction unit 254) performed by example video encoder 20 will be described in more detail below.

Partitioning The partitioning unit 262 is capable of partitioning (or splitting) the current block 203 into smaller partitions, such as smaller blocks of square or rectangular size. These smaller blocks (sometimes referred to as sub-blocks) may be further partitioned into even smaller partitions. This is also called tree partitioning or hierarchical tree partitioning, where, for example, the root block at root tree level 0 (hierarchical level 0, depth 0) is recursively partitioned, e.g. It can be partitioned into two or more blocks at a tree level, for example nodes at tree level 1 (hierarchy level 1, depth 1), and these blocks are partitioned into two or more blocks at the next lower level. partitioning ends, e.g. to tree level 2 (hierarchical level 2, depth 2), etc., due to a termination criterion being met, e.g. a maximum tree depth or a minimum block size being reached. It is possible to re-partition up to Additionally, blocks that are not partitioned are also referred to as leaf blocks or leaf nodes of the tree. A tree with partitioning into two partitions is a binary tree (BT), a tree with partitioning into three partitions is a ternary tree (TT), and a tree with partitioning into four partitions is a quadrilateral tree. It is called a branch tree (QT).

As mentioned above, the term "block" as used in this application may be a portion of a picture, in particular a square or rectangular portion. For example, with reference to HEVC and VVC, blocks may include coding tree units (CTUs), coding units (CUs), prediction units (PUs), and transform units (TUs), and/or corresponding blocks, e.g. It may be or correspond to a coding tree block (CTB), a coding block (CB), a transform block (TB), or a prediction block (PB).

For example, a coding tree unit (CTU) can be a CTB for luma samples, two corresponding CTBs for chroma samples in a picture with a three sample array, or three CTBs used to code the samples. The CTB may be or include samples of pictures or monochrome pictures that are coded using separate color planes and syntax structures. Correspondingly, a coding tree block (CTB) may be an NxN block of samples for a certain value N, such that the division of components into CTBs is a partitioning. A coding unit (CU) is a coding block of luma samples, two corresponding coding blocks of chroma samples of a picture with an array of three samples, or a coding block of three chroma samples used to code the samples. It may be or include a coding block of samples of pictures or monochrome pictures that are coded using separate color planes and syntax structures. Correspondingly, a coding block (CB) may be an MxN block of samples for certain values of M and N, such that the division of the CTB into coding blocks is a partitioning.

In embodiments, for example according to HEVC, a coding tree unit (CTU) may be divided into CUs by using a quadtree structure, denoted as a coding tree. The decision whether to code a picture area using inter-picture (temporal) or intra-picture (spatial) prediction is made at the leaf CU level. Each leaf CU can be further divided into one, two, or four PUs depending on the PU partition type. Within one PU, the same prediction process is applied and relevant information is sent to the decoder on a PU basis. After obtaining the residual block by applying a prediction process based on the PU partition type, the CU is partitioned into transform units (TUs) according to another quadtree structure similar to the coding tree of the CU. is possible.

In embodiments, the coding blocks may be partitioned, e.g., by combinatorial quadtree and binary tree (QTBT) partitioning, e.g. used to. In the QTBT block structure, the CU can have either square or rectangular shape. For example, a coding tree unit (CTU) is first partitioned by a quadtree structure. The quadtree leaf nodes are further partitioned by a binary or ternary tree (or triple) structure. Partitioning the tree leaf nodes is called a coding tree unit (CU), and that segmentation is used for prediction and transformation processing without any further partitioning. This means that CU, PU, TU have the same block size in QTBT coding block structure. In parallel, multiple partitions, such as triple tree partitions, may be used with the QTBT block structure.

In one example, mode selection unit 260 of video encoder 20 may be configured to perform any combination of the partitioning techniques described herein.

As mentioned above, video encoder 20 is configured to determine or select a best or optimal prediction mode from a (eg, predetermined) set of prediction modes. The set of prediction modes may include, for example, an intra prediction mode and/or an inter prediction mode.

Intra prediction The set of intra prediction modes may include 35 different intra prediction modes, e.g. DC (or average) mode and non-directional modes such as planar mode, or directional modes e.g. as specified in HEVC. or may include 67 different intra-prediction modes, e.g. non-directional modes such as DC (or average) mode and planar mode, or directional modes, e.g. as specified in VVC. .

Intra prediction unit 254 is configured to generate intra prediction block 265 using reconstructed samples of neighboring blocks of the same current picture according to an intra prediction mode of the set of intra prediction modes.

Intra prediction unit 254 (or, in general, mode selection unit 260) provides intra prediction parameters (or, in general, is further configured to output information indicating a selected intra-prediction mode for the block, such that, for example, video decoder 30 can receive and use the prediction parameters for decoding. . Intra prediction unit 254 may include an intra sub-partition (ISP) coding mode, which may further divide the coding unit into several prediction blocks and predict them in sequence. .

Inter Prediction The set of (or possible) inter prediction modes is based on available reference pictures (i.e., at least partially decoded previous pictures, e.g. those stored in DPB 230) and other inter prediction modes. Prediction parameters, e.g. whether the whole or only part of the reference picture, e.g. whether a search window area around the area of the current block of the reference picture is used to search for the best matching reference block; and/or Or it depends, for example, on whether half/semi-pel, quarter-pel interpolation is applied, etc.

In addition to the above prediction modes, a skip mode and/or a direct mode may be applied.

Inter prediction unit 244 may include a motion estimation (ME) unit and a motion compensation (MC) unit (both not shown in FIG. 2). The motion estimation unit extracts a picture block 203 (current picture block 203 of current picture 17) and a decoded picture 231 or at least one or more previously reconstructed blocks for motion estimation. , for example configured to receive or obtain reconstructed blocks of one or more other/different previously decoded pictures 231. For example, a video sequence may include a current picture and a previously decoded picture 231, or in other words, a current picture and a previously decoded picture 231 or may form a sequence of pictures.

The encoder 20 may, for example, select a reference block from a plurality of reference blocks of the same or different pictures of a plurality of other pictures, and select the reference block (or reference picture index) and/or the position (x,y coordinates) of the reference block. and the position of the current block (spatial offset) may be arranged to provide the motion estimation unit (not shown in FIG. 2) as an inter-prediction parameter. This offset is also called a motion vector (MV).

The motion compensation unit is configured to obtain, eg, receive, inter-prediction parameters and perform inter-prediction based on or using the inter-prediction parameters to obtain inter-prediction blocks 265. The motion compensation performed by the motion compensation unit may include fetching or generating predictive blocks based on motion/block vectors determined by motion estimation, potentially performing interpolation to sub-pixel precision. is possible. Interpolative filtering can generate additional pixel samples from known pixel samples, thus potentially increasing the number of candidate predictive blocks that can be used to code a picture block. . Upon receiving the motion vector for the PU of the current picture block, the motion compensation unit may locate the predictive block pointed to by the motion vector in one of the reference picture lists.

The motion compensation unit may also generate syntax elements associated with the blocks and video slices for use by video decoder 30 in decoding the picture blocks of the video slices. In addition to or as an alternative to slices and their respective syntax elements, tile groups and/or tiles and their respective syntax elements may be generated or used.

Entropy Coding Entropy coding unit 270 may be configured to perform an entropy coding algorithm or scheme (e.g., variable length coding (VLC) scheme, context adaptive VLC scheme (CALVC), arithmetic coding scheme, binarization, context adaptive binary arithmetic coding (CABAC)). ), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy coding (PIPE) coding, or other entropy encoding methods or techniques), quantized residual coefficients 209, inter-prediction parameters, encoded picture data 21 that can be applied to or bypassed (uncompressed) intra prediction parameters, loop filter parameters, and/or other syntax elements and output by output 272; For example, it is arranged to obtain in the form of an encoded bitstream 21, so that for example a video decoder 30 can receive and use the parameters for decoding. Encoded bitstream 21 may be sent to video decoder 30 or stored in memory for later transmission or retrieval by video decoder 30.

Other structural variations of video encoder 20 can be used to encode video streams. For example, non-transform-based encoder 20 may directly quantize the residual signal without transform processing unit 206 for a particular block or frame. In another implementation, encoder 20 may combine quantization unit 208 and inverse quantization unit 210 into a single unit.

Decoder and Decoding Method FIG. 3 shows an example of a video decoder 30 configured to implement the techniques of the present application. Video decoder 30 is configured to receive encoded picture data 21 (e.g., encoded bitstream 21), e.g., encoded by encoder 20, to obtain decoded pictures 131. be done. Coded picture data or bitstream represents coded picture data, e.g., picture blocks (and/or tile groups or tiles) and associated syntax elements of a coded video slice. Contains information for decoding data.

In the example of FIG. 3, decoder 30 includes an entropy decoding unit 304, an inverse quantization unit 310, an inverse transform processing unit 312, a reconstruction unit 314 (e.g., an adder 314), a loop filter 320, a decoded picture buffer ( DPB ) 330, and a mode application unit 360, an inter prediction unit 344, and an intra prediction unit 354. Inter prediction unit 344 may be or include a motion compensation unit. Video decoder 30 may, in some examples, perform a decoding pass that is generally the opposite of the encoding pass described with respect to video encoder 100 in accordance with FIG.

As described with respect to encoder 20, inverse quantization unit 210, inverse transform processing unit 212, reconstruction unit 214, loop filter 220, decoded picture buffer (DPB) 230, inter prediction unit 344, and intra prediction Unit 354 is also referred to as forming the "built-in decoder" of video encoder 20. Accordingly, inverse quantization unit 310 may be functionally identical to inverse quantization unit 110, inverse transform processing unit 312 may be functionally identical to inverse transform processing unit 212, and reconstruction Unit 314 may be functionally identical to reconstruction unit 214, loop filter 320 may be functionally identical to loop filter 220, and decoded picture buffer 330 may be It may be functionally identical to the decoded picture buffer 230. Accordingly, descriptions made for each unit and function of video encoder 20 apply correspondingly to each unit and function of video decoder 30.

Entropy Decoding Entropy decoding unit 304 analyzes bitstream 21 (or encoded picture data 21 in general) and performs, for example, entropy decoding on encoded picture data 21, e.g. quantization coefficients 309 and/or decoded coding parameters (not shown in FIG. 3), e.g. inter prediction parameters (e.g. reference picture index and motion vector), intra prediction parameters (e.g. intra prediction mode or index), transformation parameters, quantization parameters, loop filter parameters, and/or other syntax elements. Entropy decoding unit 304 may be configured to apply a decoding algorithm or scheme corresponding to the encoding scheme as described with respect to entropy encoding unit 270 of encoder 20. Entropy decoding unit 304 is further configured to provide inter-prediction parameters, intra-prediction parameters and/or other syntax elements to mode application unit 360 and to provide other parameters to other units of decoder 30. may be done. Video decoder 30 may receive syntax elements at the video slice level and/or the video block level. Additionally or alternatively to slices and respective syntax elements, tile groups and/or tiles and respective syntax elements may be received and/or used.

Inverse Quantization The inverse quantization unit 310 extracts a quantization parameter (QP) (or information regarding inverse quantization in general) and a quantization coefficient from the encoded picture data 21 (e.g., analyzes and/or By decoding, e.g. by entropy decoding unit 304) and applying inverse quantization on the decoded quantized coefficients, based on the quantization parameters, unquantized, sometimes referred to as transform coefficients 311. It may be configured to obtain a coefficient of 311. The inverse quantization process processes the video for each video block within a video slice (or tile or tile group) to determine the degree of quantization and the degree of inverse quantization that should be applied as well. - may include using a quantization parameter determined by encoder 20;

Inverse Transform Inverse transform processing unit 312 receives unquantized coefficients 311, also referred to as transform coefficients 311, and applies a transform to unquantized coefficients 311 to obtain a reconstructed residual block 213 in the sample domain. It is possible to configure it as follows. Reconstructed residual block 213 may also be referred to as transform block 313. The transform may be an inverse transform, such as an inverse DCT, an inverse DST, an inverse integer transform, or a conceptually similar inverse transform process. Inverse transform processing unit 312 further receives transform parameters or corresponding information from encoded picture data 21 (e.g., by parsing and/or decoding, e.g., by entropy decoding unit 304) to It may be configured to determine a transform to be applied to the quantization coefficients 311.

Reconstruction The reconstruction unit 314 (e.g., adder or summation unit 314) adds the reconstructed residual block 313 to the prediction block 365 to make the reconstructed block 315 in the sample domain, e.g. It may be configured to obtain by adding the sample values of the residual block 313 and the sample values of the prediction block 365.

Filtering A loop filter unit 320 (either within or after the coding loop) filters the reconstructed block 315 to obtain a filtered block 321, e.g. to smooth pixel transitions, or otherwise configured to improve video quality. The loop filter unit 320 may include a deblocking filter, a sample adaptive offset (SAO) filter, or one or more other filters, such as a bilateral filter, an adaptive loop filter (ALF), a sharpening or It may include a smoothing filter, or a collaborative filter, or any combination thereof. Although loop filter unit 320 is shown in FIG. 3 as an in-loop filter, in other configurations loop filter unit 320 may be implemented as a post-loop filter.

Decoded Picture Buffer The decoded video block 321 of the picture is stored in a decoded picture buffer 330, which stores the decoded picture 331 in other pictures and/or output display. For each one, it is stored as a reference picture for subsequent motion compensation.

Decoder 30 is configured to output decoded pictures 331 , for example via output 332, for presentation or display to a user.

Prediction Inter prediction unit 344 may be identical to inter prediction unit 244 (particularly a motion compensation unit), and intra prediction unit 354 may be functionally identical to inter prediction unit 254, and partitioning and/or based on the prediction parameters or the respective information received from the encoded picture data 21 (e.g. by parsing and/or decoding, e.g. by the entropy decoding unit 304) making a partitioning or partitioning decision and prediction. Execute. The mode application unit 360 performs block-by-block prediction (intra-prediction or inter-prediction) based on the reconstructed picture, block or respective samples (filtered or unfiltered) to predict the predicted block. 365.

When a video slice is coded as an intra-coded (I) slice, intra-prediction unit 354 of mode application unit 360 combines data from previous decoded blocks of the current picture and the signaled intra-prediction. Based on the mode, it is configured to generate a prediction block 365 for the picture block of the current video slice. When a video picture is coded as an inter-coded (i.e., B or P) slice, the inter-prediction unit 344 (e.g., motion compensation unit) of the mode application unit 360 receives from the entropy decoding unit 304 The prediction block 365 is configured to generate a prediction block 365 for a video block of a current video slice based on the motion vector and another syntax element. For inter prediction, a prediction block may be generated from one reference picture in one reference picture list. Video decoder 30 may construct the reference frame lists, List0 and List1, using a default construction technique based on reference pictures stored in DPB 330. The same or similar may additionally or alternatively include tile groups (e.g., video tile groups) and/or tiles (e.g., video tiles) for slices (e.g., video slices). It can be applied to or by the embodiment used, for example the video can be coded using I, P or B tile groups and/or tiles.

Mode application unit 360 determines predictive information for the video block of the current video slice by analyzing motion vectors or related information and other syntax elements, and uses the predictive information to determine the predictive information for the video block of the current video slice. The video block is configured to generate a predictive block for a current video block. For example, mode application unit 360 may use some of the received syntax elements to determine the prediction mode (e.g., intra or inter prediction), inter prediction, or prediction mode used to code the video blocks of the video slice. The slice type (e.g., B slice, P slice, or GPB slice), configuration information for one or more of the slice's reference picture lists, the motion vector for each inter-coded video block of the slice, the slice's Determine inter-prediction status for each inter-coded video block and other information for decoding the video block within the current video slice. The same or similar may additionally or alternatively include tile groups (e.g., video tile groups) and/or tiles (e.g., video tiles) for slices (e.g., video slices). It can be applied to or by the embodiment used, for example the video can be coded using I, P or B tile groups and/or tiles.

The embodiment of video decoder 30 shown in FIG. 3 may be configured to partition and/or decode pictures by using slices (also referred to as video slices), where pictures are It can be partitioned or decoded into one or more slices (typically non-overlapping), and each slice can include one or more blocks (eg, CTUs).

The embodiment of video decoder 30 shown in FIG. 3 partitions and/or decodes pictures by using tile groups (also referred to as video tile groups) and/or tiles (also referred to as video tiles). A picture can be partitioned or decoded into one or more tile groups (typically non-overlapping), with each tile group may include, for example, one or more blocks (e.g., CTUs) or one or more tiles, each tile may be, for example, of rectangular shape and may include one or more blocks (e.g., CTU), which may contain complete or fragmented blocks, for example.

Other variations of video decoder 30 can be used to decode encoded picture data 21. For example, decoder 30 may generate an output video stream without loop filtering unit 320. For example, non-transform-based decoder 30 may dequantize the residual signal directly without inverse transform processing unit 312 for a particular block or frame. In another implementation, video decoder 30 may combine inverse quantization unit 310 and inverse transform processing unit 312 into a single unit.

It should be understood that in encoder 20 and decoder 30, the processing results of the current step may be further processed and then output to the next step. For example, after interpolation filtering, motion vector derivation, or loop filtering, further processing such as clipping or shifting may be performed on the results of the interpolation filtering, motion vector derivation, or loop filtering.

FIG. 4 is a schematic diagram of a video coding device 400 according to an embodiment of the present disclosure. Video coding device 400 is suitable for implementing the disclosed embodiments as described herein. In embodiments, video coding device 400 may be a decoder, such as video decoder 30 of FIG. 1A, or an encoder, such as video encoder 20 of FIG. 1A.

Video coding device 400 includes an inlet port 410 and a receiver unit (Rx) 420 for receiving data; a processor, logic unit, or central processing unit (CPU) 430 for processing data; and transmitting data. and a memory 460 for storing data. Video coding device 400 also includes optical-to-electrical (OE) components and electrical components coupled to ingress port 410, receiver unit 420, transmitter unit 440, and egress port 450 for ingress and egress of optical or electrical signals. - May include an optical (EO) component.

Processor 430 is implemented by hardware and software. Processor 430 may be implemented as one or more CPU chips, cores (eg, multi-core processors), FPGAs, ASICs, and DSPs. Processor 430 communicates with ingress port 410, receiver unit 420, transmitter unit 440, egress port 450, and memory 460. Processor 430 includes a coding module 470. Coding module 470 implements the disclosed embodiments described above. For example, coding module 470 implements, processes, prepares, or provides various coding operations. Accordingly, the inclusion of coding module 470 provides a significant improvement to the functionality of video coding device 400 and affects the transformation of video coding device 400 into different states. Alternatively, coding module 470 is implemented as instructions stored in memory 460 and executed by processor 430.

Memory 460 includes one or more disks, tape drives, and solid state drives and is used as an overflow data storage device to store programs when such programs are selected for execution. It is possible to store instructions and data read during the execution of a program. Memory 460 may be volatile and/or non-volatile, and may include read-only memory (ROM), random access memory (RAM), ternary content addressable memory (TCAM), and/or static random memory. It may also be an access memory (SRAM).

FIG. 5 is a simplified block diagram of an apparatus 500 that can be used as either or both source device 120 and destination device 14 of FIG. 1, according to an example embodiment.

Processor 502 within device 500 may be a central processing unit. Alternatively, processor 502 may be any other type of device or devices now existing or hereafter developed capable of manipulating or processing information. Although the disclosed implementations can be implemented using a single processor, such as processor 502, as shown, advantages in speed and efficiency may be obtained using more than one processor. .

Memory 504 within apparatus 500 may be a read-only memory (ROM) device or a random access memory (RAM) device in implementations. Any other suitable type of storage device may be used as memory 504. Memory 504 may include code and data 506 that is accessed by processor 502 using bus 512. Memory 504 may further include an operating system 508 and application programs 510, including at least one program that enables processor 502 to perform the methods described herein. including. For example, application program 510 may include applications 1 through N, which further include a video coding application that performs the methods described herein. Apparatus 500 may also include one or more output devices, such as a display 518. Display 518 may, in one example, be a touch-sensitive display that combines the display with a touch-sensitive element operable to sense touch input. Display 518 may be coupled to processor 502 via bus 512.

Although depicted herein as a single bus, bus 512 of device 500 may be comprised of multiple buses. Additionally, secondary storage 514 can be coupled directly to other components of device 500 or can be accessed via a network, and can be stored on a single storage device such as a memory card. It is possible to include multiple units, such as an integrated unit or multiple memory cards. Accordingly, apparatus 500 can be implemented in a wide variety of configurations.

Intra-subpartition (ISP) coding mode is an updated version of line-based intra-prediction (LIP) coding. The traditional version of intra sub-partition coding mode supports only one chroma subsampling (also called chroma format or chroma color format) - 4:2:0, and other chroma formats does not have any parameters for support. In particular, traditional versions of intra-sub-partition coding mode cannot operate with respect to chroma subsampling 4:4:4, which is widely used in applications. Embodiments of the present invention extend the intra sub-partition coding mode to cover all chroma subsampling.
Embodiments of the present invention propose two solutions to extend intra sub-partition coding mode to cover chroma subsampling:
1) Add two input parameters SubWidthC and SubHeightC corresponding to horizontal and vertical chroma subsampling. These parameters are used to derive the chroma conversion block size.
2) Extension of the normal case. For chroma subsampling 4:4:4, the ISP partition for chroma corresponds to the ISP partition for luma.

A (digital) picture is, or can be thought of as, a two-dimensional array or matrix of samples with intensity values. The samples in an array may also be referred to as pixels (short for picture elements) or pels. The number of samples in the horizontal and vertical directions (or axes) of an array or picture defines the size and/or resolution of the picture. Three color components are typically used for color representation, ie a picture may be represented by or include three sample arrays. In RGB format or color space, a picture includes corresponding arrays of red, green, and blue samples. However, in video coding, each pixel is typically represented in a luminance and chrominance format or color space, e.g. YCbCr, where YCbCr is the luminance component denoted Y (sometimes L is also used instead). ) and two chrominance components denoted Cb and Cr.

The luma and chroma components can have different subsamplings. For example, in the so-called 4:2:0 chroma format, each of the two chroma arrays has half the height and half the width of the luma array.

The VVC specification describes five different formats for chroma representation. These formats are presented in Table 1.
table 1. Chroma format 1 as described in the VVC specification

Each column in this table has the following meaning:
chroma_format_idc indicates chroma sampling relative to luma sampling. The value of chroma_format_idc shall be within the range of 0 to 3 inclusive.

separate_colour_plane_flag equal to 1 indicates that the three color components of the 4:4:4 chroma format are coded separately. separate_colour_plane_flag equal to 0 indicates that the color components are not coded separately. If separate_colour_plane_flag is not present, it is presumed to be equal to 0. If separate_colour_plane_flag is equal to 1, the coded picture consists of three separate components, each of which consists of coded samples of one color plane (Y, Cb or Cr), monochrome coding - Use syntax. In this case, each color plane is associated with a particular color_plane_id value.
Note 1 - There is no decoding process dependency between color planes with different color_plane_id values. For example, a decoding process for a monochrome picture with one value of color_plane_id does not use any data from a monochrome picture with a different value of color_plane_id for inter prediction.

Depending on the value of separate_color_plane_flag, the value of the variable ChromaArrayType is assigned as follows:
- If separate_colour_plane_flag is equal to 0, ChromaArrayType is set equal to chroma_format_idc.
- Otherwise (separate_colour_plane_flag is equal to 1), ChromaArrayType is set equal to 0.

The chroma format determines the priority and subsampling of the chroma array.
In monochrome sampling, there is only one sample array, nominally considered the luma array.
With 4:2:0 sampling, each of the two chroma arrays has half the height and half the width of the luma array.
With 4:2:2 sampling, each of the two chroma arrays has the same height and half the width as the luma array.
For 4:4:4 sampling, depending on the value of separate_colour_plane_flag, apply the following:
- If separate_color_plane_flag is equal to 0, each of the two chroma arrays has the same height and width as the luma array.
- Otherwise (separate_color_plane_flag equals 1), the three color planes are treated separately as monochrome sampled pictures.

The number of bits required to represent each sample in the luma and chroma arrays in a video sequence is in the range 8 to 16 inclusive, and the number of bits used in the luma array is There is a possibility that the number of bits is different from the number of bits.
When the value of chroma_format_idc is equal to 1, the nominal vertical and horizontal relative positions of luma and chroma samples in the picture are shown in FIG. Alternative chroma sample relative positions may be indicated in the video usability information.
If the value of chroma_format_idc is equal to 2, the chroma sample coexists with the corresponding luma sample, and the nominal position in the picture is shown in Figure 7.
When the value of chroma_format_idc is equal to 3, all array samples coexist for the picture in all cases, and the nominal position in the picture is shown in FIG.

The variables SubWidthC and SubHeightC are specified in Table 1 depending on the chroma format sampling structure, which in turn is specified by chroma_format_idc and separate_colour_plane_flag.
Alternatively, SubWidthC and SubHeightC can be determined as follows:
SubWidthC = (1 + log2(w _luma / w _chroma ))
SubHeightC = (1 + log2(h _luma / h _chroma )),
w _luma , h _luma are the dimensions of the luma array, and w _chroma, h _chroma are the dimensions of the corresponding chroma array. Therefore, the variables SubWidthC and SubHeightC represent the ratio between luma and chroma size.

In the first embodiment, the ISP technique performs sub-partitioning only on luma blocks, and for chroma blocks, prediction and further transformations are performed on the entire CU block without partitioning. be done. It should be noted that at the conversion unit stage, the TU of the chroma block should be treated according to the chroma format specified in the bitstream, e.g. at the SPS level, and is described in terms of luma and chroma size. It is assumed that common values are used, such as SubWidthC and SubHeightC. Table 2 below shows an example of chroma TU position and size determination for the first embodiment.

Table 2 – Example of transform_unit syntax table for the first embodiment

In Table 2, the coordinates x0, y0 and the sizes tbWidth, tbHeight represent the current luma TU block position and size; the global array CbPosX, CbPosY, CbWidth, CbHeight allows to get the CU position and size . Therefore, the coordinates and sizes xC, yC, wC, hC have been calculated to represent a chroma TU block that is equal to a chroma CU block. Depending on the chroma color format used, the chroma block size can be different from the corresponding luma block size, so when dealing with all chroma format cases, the chroma block size It should be noted that the width and height are normalized accordingly by SubWidthC and SubHeightC.

In this embodiment, the bitstream includes information indicating an intra sub-partition (ISP). For example, information indicating the ISP is a flag. The flag may be intra_subpartitions_split_flag and/or intra_subpartitions_mode_flag. After receiving the bitstream, the decoder parses the bitstream to obtain flags. The decoder then determines the ISP's information, eg, IntraSubPartitionsSplitType, based on the flag.

intra_subpartitions_mode_flag[x0][y0] equal to 1 indicates that the current intra coding unit is partitioned into rectangular transform block subpartitions of NumIntraSubPartitions[x0][y0]. intra_subpartitions_mode_flag[x0][y0] equal to 0 indicates that the current intra coding unit is not partitioned into rectangular transform block subpartitions.

If intra_subpartitions_mode_flag[x0][y0] is not present, it is presumed to be equal to 0. intra_subpartitions_split_flag[x0][y0] indicates whether the intra subpartitioning type is horizontal or vertical. If intra_subpartitions_split_flag[x0][y0] is not present, it is deduced as follows:
- If cbHeight is greater than MaxTbSizeY, intra_subpartitions_split_flag[x0][y0] is assumed to be equal to 0.
- Otherwise (cbHeight is greater than MaxTbSizeY), intra_subpartitions_split_flag[x0][y0] is assumed to be equal to 1.

The variable IntraSubPartitionsSplitType specifies the type of split used for the current luma coding block, as shown in Table 3. IntraSubPartitionsSplitType is derived as follows:
- If intra_subpartitions_mode_flag[x0][y0] is equal to 0, IntraSubPartitionsSplitType is set equal to 0.
- Otherwise, IntraSubPartitionsSplitType is
Set equal to 1 + intra_subpartitions_split_flag[x0][y0].
Table 3 - Names associated with IntraSubPartitionsSplitType

The ISP information indicating whether the ISP is used to split the luma coding blocks of the coding unit is then indicated by IntraSubPartitionsSplitType. If IntraSubPartitionsSplitType != ISP_NO_SPLIT, ISP is used to split the luma coding blocks of the coding unit.

In a second embodiment, the ISP technique performs sub-partitioning on chroma blocks that is consistent with luma block sub-partitioning when 4:4:4 subsampling is used in the bitstream. For other subsampling cases, e.g. 4:2:0 and 4:2:2, the ISP does not perform chroma partitioning and the chroma block matches the entire CU. The table below shows an example of chroma TU position and size determination for the second embodiment.

Table 4 – Example of transform_unit syntax table for second embodiment

In the table, the condition ChromaArrayType = = 3 checks if the current chroma format is 4:4:4. If positive, the two chroma cbf flags will be forced to be signaled if ISP is used (IntraSubPartitionsSplitType != ISP_NO_SPLIT), and the position and size for the chroma block will be changed according to the else branch. determined based on the location and size of the TU. In this case, the current chroma block position and size are obtained from the TU position and coordinates.

In the second embodiment, the value of ntraSubPartitionsSplitType can be determined in the same manner as described in the first embodiment.

FIG. 9 shows an embodiment of a method for intra sub-partition (ISP) coding implemented by a decoding device according to the invention. The decoding device may be video decoder 30 of FIG. 1A or decoder 30 of FIG. 3. The method of ISP coding includes the following steps. In step 901, the decoding device obtains ISP information. As mentioned above, the decoding device can analyze the bitstream received from the encoding device. The bitstream includes information indicating the ISP, such as intra_subpartitions_split_flag and/or intra_subpartitions_mode_flag. Next, the decoding device obtains IPS information, such as IntraSubPartitionsSplitType, based on intra_subpartitions_split_flag and/or intra_subpartitions_mode_flag.

In step 902, the decoding device determines whether a first condition is satisfied;
The first condition is: 1) a single tree is used to partition the coding unit, and 2) the ISP information indicates that the ISP is used to partition the luma coding blocks. Including what is shown. The expression “IntraSubPartitionsSplitType != ISP_NO_SPLIT” means that the ISP information indicates that the ISP is used to split the luma coding blocks. The expression “treeType = = SINGLE_TREE” means that a single tree is used to partition the coding unit.

In step 903, the decoding device determines the size of a chroma transform block (TB) of the coding unit based on SubWidthC and SubHeightC, where SubWidthC and SubHeightC are chroma format information The chroma format information indicates the chroma format of the picture to which the coding unit belongs, and the chroma format is 4:2:0, 4:2:2, or 4:4: Contains at least one of 4.

The decoding device may determine the size of the chroma TB based on SubWidthC and SubHeightC and also based on the size of the luma coding block of the coding unit. For example, the size of the chroma transform block is:
wC = CbWidth[x0][y0] / SubWidthC; and
hC = CbHeight[x0][y0] / SubHeightC;
, where wC represents the width of the chroma conversion block, hC represents the height of the chroma conversion block, CbWidth represents the width of the luma coding block, and CbHeight represents the height of the luma coding block.

The size of the chroma conversion block follows the rules below:
- if the chroma format is equal to 4:4:4, the size of the chroma conversion block is equal to the size of the luma coding block;
- Otherwise, the size of the chroma conversion block is determined as a function of the luma coding block size and the chroma format;
determined according to

The decoding device is capable of determining the size of the chroma TB if a first condition and a second condition are satisfied, and the second condition specifies that the variable ChromaArrayType is not equal to a default value, e.g. 3. include.

FIG. 10 shows an embodiment of a method for intra sub-partition (ISP) coding implemented by a coding device according to the invention. The encoding device may be video encoder 20 of FIG. 1A or encoder 20 of FIG. 2. The method of ISP coding includes the following steps.
In step 1001, the encoding device determines whether a first condition is satisfied, the first condition being: 1) a single tree is used to partition the coding unit; and 2) Including the use of ISP to partition luma coding blocks. The expression “IntraSubPartitionsSplitType != ISP_NO_SPLIT” means that ISP is used to split the luma coding blocks. The expression “treeType = = SINGLE_TREE” means that a single tree is used to partition the coding unit.

In step 1002, the encoding device determines the size of a chroma transform block (TB) of the coding unit based on SubWidthC and SubHeightC, where SubWidthC and SubHeightC are chroma format information The chroma format information indicates the chroma format of the picture to which the coding unit belongs, and the chroma format is 4:2:0, 4:2:2, or 4:4: Contains at least one of 4.

The encoding device may determine the size of the chroma TB based on SubWidthC and SubHeightC and also based on the size of the luma coding block of the coding unit. For example, the size of the chroma transform block is:
wC = CbWidth[x0][y0] / SubWidthC; and
hC = CbHeight[x0][y0] / SubHeightC;
, where wC represents the width of the chroma conversion block, hC represents the height of the chroma conversion block, CbWidth represents the width of the luma coding block, and CbHeight represents the height of the luma coding block.

The size of the chroma conversion block follows the rules below:
- if the chroma format is equal to 4:4:4, the size of the chroma conversion block is equal to the size of the luma coding block;
- Otherwise, the size of the chroma conversion block is determined as a function of the luma coding block size and the chroma format;
determined according to

The encoding device is capable of determining the size of the chroma TB if a first condition and a second condition are satisfied, and the second condition specifies that the variable ChromaArrayType is not equal to a default value, e.g. 3. include.

In step 1003, the encoding device encodes the bitstream, the bitstream including information indicating that the ISP is used to divide the luma coding blocks of the coding unit. For example, the bitstream includes information indicating the ISP, such as intra_subpartitions_split_flag and/or intra_subpartitions_mode_flag.

FIG. 11 shows an embodiment of a decoding apparatus 1100 for intra sub-partitions (ISPs). Decoding device 1100 may be video decoder 30 of FIG. 1A or decoder 30 of FIG. 3. The device 1100 includes an acquisition unit 1101 and a determination unit 1102. The acquisition unit 1101 is configured to acquire ISP information, where the ISP information indicates whether the ISP is used to divide the luma coding blocks of the coding unit. The determining unit 1102 is configured to determine the size of a chroma transform block (TB) of the coding unit based on SubWidthC and SubHeightC, where SubWidthC and SubHeightC are chroma format information It is a variable that depends on . The chroma format information indicates the chroma format of the picture to which the coding unit belongs, and the chroma format is at least one of 4:2:0, 4:2:2, or 4:4:4. including. The first condition is: 1) a single tree is used to partition the coding unit, and 2) the ISP information indicates that the ISP is used to partition the luma coding blocks. Including what is shown.

The decoding device is configured to perform the method as described in FIG. 9 and other embodiments above. For example, the decision unit 1102 uses the following rules:
- if the chroma format is equal to 4:4:4, the size of the chroma conversion block is equal to the size of the luma coding block;
- otherwise, the size of the chroma conversion block is determined as a function of the luma coding block size and the chroma format;
The chroma conversion block is configured to determine the size of the chroma conversion block according to the chroma conversion block size.

The determining unit may be configured to determine the size of the chroma transform block of the coding unit based on SubWidthC and SubHeightC if a first condition and a second condition are satisfied, the second condition being a variable Contains ChromaArrayType not equal to default value.

FIG. 12 shows an embodiment of an encoding apparatus 1200 for intra-subpartition (ISP). Encoding device 1200 may be video encoder 20 of FIG. 1A or encoder 20 of FIG. 2. Apparatus 1200 includes a determining unit 1201 and an encoding unit 1202. The determining unit 1201 is configured to determine the size of the chroma transform block of the coding unit based on SubWidthC and SubHeightC if at least the first condition is fulfilled. SubWidthC and SubHeightC are two variables that depend on chroma format information. The chroma format information indicates the chroma format of the picture to which the coding unit belongs, and the chroma format is at least one of 4:2:0, 4:2:2, or 4:4:4. including. The first condition includes that a single tree is used to partition the coding unit and that an ISP is used to partition the luma coding blocks of the coding unit. Encoding unit 1202 is configured to encode a bitstream, where the bitstream includes information indicating that an ISP is used to partition luma coding blocks of the coding unit.

The encoding device is configured to perform the method as described in FIG. 10 and other embodiments above. For example, decision unit 1201:
wC = CbWidth[x0][y0] / SubWidthC; and
hC = CbHeight[x0][y0] / SubHeightC;
is configured to determine the size of the chroma transform block according to the width of the chroma transform block, wC represents the width of the chroma transform block, hC represents the height of the chroma transform block, CbWidth represents the width of the luma coding block, and CbHeight represents the height of the luma coding block.

The decision unit 1201 is
SubWidthC = (1 + log2(w _luma / w _chroma ));
SubHeightC = (1 + log2(h _luma / h _chroma ));
SubWidthC and SubHeightC may be configured to determine SubWidthC and SubHeightC according to the following: w _luma , h _luma are dimensions corresponding to a luma array, and w _chroma , h _chroma are dimensions corresponding to a chroma array.

Decision unit 1201 follows the rules:
- if the chroma format is equal to 4:4:4, the size of the chroma conversion block is equal to the size of the luma coding block;
- otherwise, the size of the chroma conversion block is determined as a function of the luma coding block size and the chroma format;
It is also configured to determine the size of the chroma conversion block according to the chroma conversion block size.

The determining unit 1201 is configured to determine the size of the chroma transform block of the coding unit based on SubWidthC and SubHeightC if a first condition and a second condition are satisfied, and the second condition is such that the variable ChromaArrayType is Including not equal to the default value.

The present application further provides the following embodiments:
Embodiment 1. A method of coding performed by a decoding device, the method comprising:
parsing the bitstream, the bitstream including intra sub-partition (ISP) coding mode information;
determining a chroma transform unit (TU) for a block coded in an ISP coding mode, the size of the chroma transform unit being dependent on the chroma format;

Embodiment 2. In the method of embodiment 1, the size of the chroma conversion unit also depends on the size of the luma coding block.

Embodiment 3. In the method of embodiment 1 or 2, the size of the chroma conversion unit is:
wC = CbWidth[x0][y0] / SubWidthC; and
hC = CbHeight[x0][y0] / SubHeightC;
where wC represents the width of the chroma TU, wC represents the height of the chroma TU, SubWidthC and SubHeightC are variables that depend on the chroma format, and CbWidth and CbHeight are global arrays.

Embodiment 4. In the method of embodiment 3, SubWidthC and SubHeightC are:
SubWidthC = (1 + log2(w _luma / w _chroma ));
SubHeightC = (1 + log2(h _luma / h _chroma ));
w _luma , h _luma are the dimensions corresponding to the luma array, and w _chroma , h _chroma are the dimensions corresponding to the chroma array.

Embodiment 5. In the method of Embodiment 1, the size of the chroma conversion unit is determined according to the following rules:
- if the chroma format is equal to 4:4:4, the size of the chroma conversion unit is equal to the size of the corresponding luma conversion unit;
- otherwise the size of the chroma conversion unit is equal to the size of the corresponding luma coding unit;
determined according to

Embodiment 6. The method of embodiment 5, wherein the size of the chroma conversion unit is determined according to the following table:

Embodiment 7. The method of any one of embodiments 1-6, the method further comprising:
Determining a luma transform unit of a block coded according to the ISP coding mode.

Embodiment 8. A method of coding performed by an encoding device, comprising:
determining a chroma transform unit (TU) for a block coded in an intra sub-partition (ISP) coding mode, the size of the chroma transform unit being dependent on the chroma format; and encoding the stream, the bitstream including ISP coding mode information;

Embodiment 9. The method of embodiment 8, wherein the size of the chroma conversion unit also depends on the size of the luma coding block.

Embodiment 10. The method of embodiment 8 or 9, in which the size of the chroma conversion unit is:
wC = CbWidth[x0][y0] / SubWidthC; and
hC = CbHeight[x0][y0] / SubHeightC;
where wC represents the width of the chroma TU, wC represents the height of the chroma TU, SubWidthC and SubHeightC are variables that depend on the chroma format, and CbWidth and CbHeight are global arrays.

Embodiment 11. The method of embodiment 10, in which SubWidthC and SubHeightC are:
SubWidthC = (1 + log2(w _luma / w _chroma ));
SubHeightC = (1 + log2(h _luma / h _chroma ));
w _luma , h _luma are the dimensions of the luma array, and w _chroma , h _chroma are the dimensions corresponding to the chroma array.

Embodiment 12. In the method of Embodiment 8, the size of the chroma conversion unit is determined according to the following rules:
- if the chroma format is equal to 4:4:4, the size of the chroma conversion unit is equal to the size of the corresponding luma conversion unit;
- otherwise the size of the chroma conversion unit is equal to the size of the corresponding luma coding unit;
determined according to

Embodiment 13. The method of embodiment 12, wherein the size of the chroma conversion unit is determined according to the following table:

Embodiment 14. The method of any one of embodiments 8-13, the method further comprising:
Determining a luma transform unit of a block coded according to the ISP coding mode.

Embodiment 15. A method of coding performed by a decoding device, the method comprising:
parsing the bitstream, the bitstream including chroma format information;
The method includes determining a size of a chroma transform unit (TU) based on the chroma format.

Embodiment 16. The method of embodiment 15, in which the size of the chroma conversion unit is:
wC = CbWidth[x0][y0] / SubWidthC; and
hC = CbHeight[x0][y0] / SubHeightC;
wC represents the width of the chroma TU, hC represents the height of the chroma TU, SubWidthC and SubHeightC are variables that depend on the chroma format, and CbWidth and CbHeight are the width and height of the coding block, respectively. It is.

Embodiment 17. The method of embodiment 16, in which SubWidthC and SubHeightC are:
SubWidthC = (1 + log2(w _luma / w _chroma ));
SubHeightC = (1 + log2(h _luma / h _chroma ));
w _luma , h _luma are the dimensions corresponding to the luma array, and w _chroma , h _chroma are the dimensions corresponding to the chroma array.

Embodiment 18. The method of any one of embodiments 15-17, in which the size of the chroma conversion unit is determined according to the following rules:
- if the chroma format is equal to 4:4:4, the size of the chroma conversion unit is equal to the size of the corresponding luma conversion unit;
- otherwise the size of the chroma conversion unit is equal to the size of the corresponding coding unit;
determined according to

Embodiment 19. The method of any one of embodiments 15-18, wherein the chroma TU is coded according to an intra sub-partition (ISP) coding mode.

Embodiment 20. The method of embodiment 19, wherein the size of the chroma conversion unit is determined according to the following table:

Hereinafter, application examples of the encoding method and decoding method shown in the above embodiments and a system using them will be described.

Embodiments of the present invention extend the intra sub-partition coding mode to cover all chroma subsampling. Thus, an accurate and versatile method for determining the size of a chroma transform block (TB) of a coding unit for ISP is achieved.

FIG. 13 is a block diagram showing a content supply system 3100 for realizing a content distribution service. The content delivery system 3100 includes a capture device 3102, a terminal device 3106, and optionally a display 3126. Capture device 3102 communicates with terminal device 3106 via communication link 3104. The communication link may include the communication channel 13 described above. Communication link 3104 includes, but is not limited to, WIFI, Ethernet, cable, wireless (3G/4G/5G), USB, or any type of combination thereof.

Capture device 3102 may generate data and encode the data according to an encoding method as shown in the embodiments above. Alternatively, the capture device 3102 can distribute the data to a streaming server (not shown), which encodes the data and transmits the encoded data to the terminal device 3106. Capture device 3102 includes, but is not limited to, a camera, a smartphone or pad, a computer or laptop, a video conferencing system, a PDA, a vehicle-mounted device, or any combination thereof. For example, capture device 3102 may include source device 12 as described above. If the data includes video, video encoder 20 included in capture device 3102 may actually perform the video encoding process. If the data includes audio (ie, voice), an audio encoder included in the capture device 3102 may actually perform the audio encoding process. In some practical scenarios, the capture device 3102 distributes encoded video and audio data by multiplexing them together. In other practical scenarios, such as video conferencing systems, encoded audio data and encoded video data are not multiplexed. Capture device 3102 separately distributes encoded audio data and encoded video data to terminal devices 3106.

In content provision system 3100, terminal device 310 receives and plays encoded data. Terminal devices 3106 include a smartphone or pad 3108, a computer or laptop 3110, a network video recorder (NVR)/digital video recorder (DVR) 3112, a TV 3114, a set top box (STB) 3116, a video conferencing system 3118, a video surveillance system 3120, a personal digital assistant (PDA) 3122, an in-vehicle device 3124, or any combination thereof, or the like capable of decoding the encoded data described above. It may be a device with reception and recovery capabilities. For example, terminal device 3106 may include destination device 14 as described above. If the encoded data includes video, a video decoder 30 included in the terminal device is prioritized to perform video decoding. If the encoded data includes audio, an audio decoder included in the terminal device is prioritized to perform the audio decoding process.

A terminal device with a display, such as a smartphone or pad 3108, a computer or laptop 3110, a network video recorder (NVR)/digital video recorder (DVR) 3112, a TV 3114, a personal digital assistant (PDA) 3122, Or in the case of an onboard device 3124, the terminal device can provide the decoded data to its display. For example, for terminal devices without a display, such as the STB 3116, video conferencing system 3118, or video surveillance system 3120, an external display 3126 is connected thereto to receive and display the decoded data.
When each device in the system performs encoding or decoding, a picture encoding device or a picture decoding device can be used, as shown in the embodiments above.

FIG. 14 is a diagram showing the configuration of an example of the terminal device 3106. After terminal device 3106 receives the stream from capture device 3102, protocol processing unit 3202 analyzes the transmission protocol of the stream. Protocols include Real Time Streaming Protocol (RTSP), Hypertext Transfer Protocol (HTTP), HTTP Live Streaming Protocol (HLS), MPEG-DASH, Real Time Transport Protocol (RTP), and Real Time Messaging. - protocols (RTMP), or any kind of combination thereof, etc., but are not limited to these.
A stream file is generated after protocol processing unit 3202 processes the stream. The file is output to demultiplexing unit 3204. Demultiplexing unit 3204 can separate the multiplexed data into encoded audio data and encoded video data. As mentioned above, for some practical scenarios, for example in a video conferencing system, encoded audio data and encoded video data are not multiplexed. In this situation, the encoded data is sent to video decoder 3206 and audio decoder 3208 without going through demultiplexing unit 3204.

The demultiplexing process produces a video element stream (ES), an audio ES, and optionally subtitles. The video decoder 3206, which includes the video decoder 30 as described in the above embodiments, decodes the video ES to generate video frames by the decoding method as shown in the above embodiments, and decodes this data. Supplied to synchronization unit 3212. Audio decoder 3208 decodes the audio ES to generate audio frames and provides this data to synchronization unit 3212. Alternatively, the video frame may be stored in a buffer (not shown in FIG. 14 ) before providing it to synchronization unit 3212. Similarly, the audio frame may be stored in a buffer (not shown in FIG . 14 ) before providing it to the synchronization unit 3212.

A synchronization unit 3212 synchronizes video and audio frames and provides video/audio to a video/audio display 3214. For example, synchronization unit 3212 synchronizes the presentation of video and audio information. Information may be syntactically coded using timestamps regarding the presentation of the coded audio and visual data and timestamps regarding the delivery of the data stream itself.

If subtitles are included in the stream, subtitle decoder 3210 decodes the subtitles, synchronizes them with video and audio frames, and provides the video/audio/subtitles to video/audio/subtitle display 3216.

Mathematical Operators The mathematical operators used in this application are similar to those used in the C programming language. However, the results of integer division and arithmetic shift operations are more precisely defined, and additional operations such as exponentiation and real-valued division are specified. Numbering and counting conventions generally start at 0, eg, "1st" is equivalent to 0th, "2nd" is equivalent to 1st, and so on.

Arithmetic Operators The following arithmetic operators are defined as follows:

Logical Operators The following logical operators are defined as follows:
x&&y Boolean logic “and” for x and y
Boolean logic “or” for x||yx and y
! Boolean logic “not”
x?y: Evaluate the value of y if zx is TRUE or not equal to 0; otherwise evaluate the value of z.

Relational Operators The following relational operators are defined as follows:
> Greater than >= Greater than or equal to < Less than <= Less than or equal to == Equal to! = not equal to

When a relational operator is applied to a syntax element or variable for which the value "na" (not applicable) is specified, the value "na" is treated as a separate value for that syntax element or variable. The value "na" is not considered equal to any other value.

Bit-wise operators The following bit-wise operators are specified as follows:
& bit wise “and”. When acting on an integer argument, it operates on the two's complement representation of the integer value. When operating on a binary argument, if the binary argument contains fewer bits than other arguments, the shorter argument is extended by adding more significant bits equal to zero.
｜ Bitwise “or”. When acting on an integer argument, it operates on the two's complement representation of the integer value. When operating on a binary argument, if the binary argument contains fewer bits than other arguments, the shorter argument is extended by adding more significant bits equal to zero.
^ Bit-wise “exclusive or”. When acting on an integer argument, it operates on the two's complement representation of the integer value. When operating on a binary argument, if the binary argument contains fewer bits than other arguments, the shorter argument is extended by adding more significant bits equal to zero.
x>>y The two's complement integer representation of x is arithmetic shifted to the right by the binary number y. This function is defined only for non-negative integer values of y. The bit shifted to the most significant bit (MSB) as a result of the right shift is equal to the MSB of x before the shift operation.
x<<y The two's complement integer representation of x is arithmetic left-shifted by the binary number y. This function is defined only for non-negative integer values of y. The bits shifted to the least significant bit (LSB) as a result of the left shift have a value equal to zero.

Assignment Operators The following arithmetic operators are defined as follows:
= assignment operator ++ increment. That is, x++ is equal to x=x+1. When used with an array index, evaluates the value of the variable before the increment operation.
-- Decrement. That is, x-- is equal to x=x-1. When used with an array index, evaluates the value of the variable before the decrement operation.
+= Increment by the specified amount. That is, x+=3 is equal to x=x+3. x+=(-3) is equal to x=x+(-3).
-= Decrement by the specified amount. That is, x-=3 is equal to x=x-3. x-=(-3) is equal to x=x-(-3).

Range Notation The following notation is used to specify a range of values:
x=y. ．． z x takes an integer value starting from y and ending at z inclusive, x, y, and z are integers, and z is greater than y.

Mathematical Functions The following mathematical functions are defined:

Order of Precedence of Operations If priority is not explicitly specified in the expression by the use of parentheses, the following rules apply:
- Higher priority operations are evaluated before any lower priority operations.
- Operations with the same priority are evaluated in order from left to right.

The table below shows the priority of operations from highest to lowest, with higher positions in the table indicating higher priority.

With respect to operators that are also used in the C programming language, the order of precedence used herein is the same as that used in the C programming language.
Table: Operation priority from highest (top in table) to lowest (bottom in table)

Text description of logical operators In text, the following format:
if( condition 0 )
statement 0
else if( condition 1 )
statement 1
...
else /* informative remark on remaining condition */
statement n
A statement of a logical operator such that it can be written mathematically can be written in the following way:
... as follows / ... the following applies:
- If condition 0, statement 0
- Otherwise, if condition 1, statement 1
-...
- Otherwise (informative remark on remaining condition), statement n

Each "If ... Otherwise, if ... Otherwise, ..." statement in the text is defined as "... as follows" or "... the following applies" immediately following "If..." ” will be introduced with. The final condition of "If ... Otherwise, if ... Otherwise, ..." is always "Otherwise, ...". Alternate "If ... Otherwise, if ... Otherwise, ..." statements match "... as follows" or "... the following applies" to a trailing "Otherwise, ..." It is possible to identify by

In text, the following format:
if( condition 0a && condition 0b )
statement 0
else if( condition 1a || condition 1b )
statement 1
...
else
statement n
A statement of a logical operator such that it can be written mathematically can be written in the following way:
... as follows / ... the following applies:
- statement 0 if all of the following conditions are true:
- condition 0a
- condition 0b
- Otherwise, if one or more of the following conditions are true, statement 1:
- condition 1a
- condition 1b
-...
- otherwise, statement n

In text, the following format:
if( condition 0 )
statement 0
if( condition 1 )
statement 1
A statement of a logical operator such that it can be written mathematically can be written in the following way:
If condition 0, then statement 0
If condition 1, then statement 1

Although embodiments of the present invention are described primarily based on video coding, embodiments of coding system 10, encoder 20 and decoder 30 (and corresponding system 10), as well as other embodiments described herein It should be noted that embodiments may be configured for still picture processing or coding, i.e. for processing or coding individual pictures independent of any preceding or consecutive pictures, as in video coding. . Generally, in cases where picture processing coding is limited to a single picture 17, only inter prediction units 244 (encoder) and 344 (decoder) may not be available. All other functions (also referred to as tools or techniques) of video encoder 20 and video decoder 30 include still picture processing, e.g. residual calculation 204/304, transform 206, quantization 208, dequantization 210/310 , (inverse) transform 212/312, partitioning 262/362, intra prediction 254/354, and/or loop filtering 220, 320, and entropy encoding 270 and entropy decoding 304.

For example, embodiments of encoder 20 and decoder 30, and the functionality described herein in connection with encoder 20 and decoder 30, may be implemented in hardware, software, firmware, or any combination thereof. . If implemented in software, the functions may be stored as one or more instructions or code on a computer-readable medium or transmitted over a communication medium and executed by a hardware-based processing unit. . Computer-readable media refers to computer-readable storage media corresponding to tangible media, such as data storage media, or any medium that facilitates transfer of a computer program from one place to another, e.g. according to a communication protocol. may include a communication medium that includes. Thus, computer-readable media generally may correspond to (1) tangible computer-readable storage media that is non-transitory, or (2) a communication medium such as a signal or carrier wave. A data storage medium can be any device that can be accessed by one or more computers or one or more processors to retrieve instructions, code, and/or data structures for implementation of the techniques described in this disclosure. may be available media. A computer program product may include a computer readable medium.

By way of example, and without limitation, such computer readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, etc. , or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. It is possible to include. Also, any connection is properly referred to as a computer-readable medium. For example, using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave to connect websites, servers, or other remote sources. Coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of a medium if the instructions are transmitted from the medium. However, it is understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals or other transitory media, but rather relate to non-transitory tangible storage media. Should. Discs and discs as used herein include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy discs and Blu-ray discs, where discs typically store data on a magnetic The disc uses a laser to optically reproduce the data. Combinations of the above should also be included within the scope of computer-readable media.

The instructions may be implemented on one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuits. can be executed by one or more processors such as Accordingly, the term "processor" as used herein may refer to any of the aforementioned structures or any other structure suitable for implementing the techniques described herein. Furthermore, in some aspects, the functionality described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or incorporated into a combined codec. You may be The techniques can also be implemented entirely with one or more circuits or logic elements.

The techniques of this disclosure can be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC), or a set of ICs (eg, a chip set). Although this disclosure describes various components, modules, or units to emphasize functional aspects of devices configured to implement the disclosed techniques, implementation by different hardware units is not necessarily required. I don't need it. Rather, as described above, the various units may be combined within a codec hardware unit, with appropriate software and/or firmware, or interoperable, including one or more processors as described above. It may also be provided by a collection of hardware units.

Claims (20)

A method of coding performed by a decoding device, comprising:
receiving a bitstream, the bitstream including a flag, the flag including at least one of a mode flag or a splitting flag, the mode flag being a transform block whose coding unit is rectangular; - indicating whether to be partitioned into sub-partitions, the splitting flag indicating whether the splitting type of the intra-sub-partition (ISP) is horizontal or vertical;
obtaining ISP information based on the flag, the ISP information indicating whether an ISP is used to divide luma coding blocks of the coding unit;
determining the size of a chroma transform block (TB) of the coding unit based on SubWidthC and SubHeightC, where SubWidthC and SubHeightC are variables dependent on chroma format information, if at least a first condition is satisfied; and the chroma format information indicates a chroma format of a picture to which the coding unit belongs, and the chroma format is 4:2:0, 4:2:2, or 4:4:4. and the first condition is: 1) a single tree is used to partition the coding unit, and 2) the ISP information is used for the luma coding. - a step including indicating that the ISP is used to divide the block;
method including. 2. The method of claim 1, wherein the size of the chroma conversion block also depends on the size of the luma coding block. The size of the chroma conversion block is:
wC = CbWidth[x0][y0] / SubWidthC; and
hC = CbHeight[x0][y0] / SubHeightC;
, wC represents the width of the chroma conversion block, hC represents the height of the chroma conversion block, CbWidth represents the width of the luma coding block, and CbHeight represents the height of the luma coding block. 3. The method of claim 2, wherein the mode flag is intra_subpartitions_mode_flag;
intra_subpartitions_mode_flag equal to 1 indicates that the current intra coding unit is partitioned into NumIntraSubPartitions rectangular transform block subpartitions;
intra_subpartitions_mode_flag equal to 0 indicates that the current intra coding unit is not partitioned into rectangular transform block subpartitions;
2. The method of claim 1, wherein intra_subpartitions_mode_flag is presumed to be equal to 0 if absent. The split flag is intra_subpartitions_split_flag;
If intra_subpartitions_split_flag does not exist:
If cbHeight is greater than MaxTbSizeY, intra_subpartitions_split_flag is assumed to be equal to 0;
2. The method of claim 1, wherein intra_subpartitions_split_flag is assumed to be equal to 1 otherwise (if cbWidth is greater than MaxTbSizeY). The size of the chroma conversion block follows the following rules:
if the chroma format is equal to 4:4:4, the size of the chroma conversion block is equal to the size of the luma coding block;
otherwise, the size of the chroma conversion block is determined as a function of the size of the luma coding block and the chroma format;
3. The method according to claim 2, wherein the method is determined according to. The ISP information is indicated by IntraSubPartitionsSplitType; and
2. The method of claim 1, wherein ISP is used to split the luma coding blocks of the coding unit if IntraSubPartitionsSplitType != ISP_NO_SPLIT. An encoding device for intra sub-partition (ISP), comprising:
one or more processors;
a non-transitory computer-readable storage medium coupled to the one or more processors and storing instructions;
and the instructions, when executed by the one or more processors, cause the one or more processors to:
determining the size of a chroma transform block of the coding unit based on SubWidthC and SubHeightC if at least a first condition is satisfied, wherein SubWidthC and SubHeightC are variables dependent on chroma format information; The chroma format information indicates a chroma format of a picture to which the coding unit belongs, and the chroma format is at least 4:2:0, 4:2:2, or 4:4:4. and the first condition is: 1) a single tree is used to partition the coding unit, and 2) to partition luma coding blocks of the coding unit. using an intra sub-partition (ISP);
encoding a bitstream, the bitstream including the values of flags, the flags including at least one of a mode flag or a splitting flag, the mode flags indicating that the coding unit indicating whether to be partitioned into rectangular transform block subpartitions, the partition flag indicating whether the ISP partition type is horizontal or vertical;
A device that executes. 9. The apparatus of claim 8, wherein the size of the chroma conversion block also depends on the size of the luma coding block. The size of the chroma conversion block is:
wC = CbWidth[x0][y0] / SubWidthC; and
hC = CbHeight[x0][y0] / SubHeightC;
where wC represents the width of the chroma conversion block, hC represents the height of the chroma conversion block, CbWidth represents the width of the luma coding block, and CbHeight represents the height of the luma coding block. 9. The device of claim 8, wherein the device represents the mode flag is intra_subpartitions_mode_flag;
intra_subpartitions_mode_flag equal to 1 indicates that the current intra coding unit is partitioned into NumIntraSubPartitions rectangular transform block subpartitions;
intra_subpartitions_mode_flag equal to 0 indicates that the current intra coding unit is not partitioned into rectangular transform block subpartitions;
9. The apparatus of claim 8, wherein intra_subpartitions_mode_flag is presumed to be equal to 0 if absent. The split flag is intra_subpartitions_split_flag;
If intra_subpartitions_split_flag does not exist:
If cbHeight is greater than MaxTbSizeY, intra_subpartitions_split_flag is assumed to be equal to 0;
9. The apparatus of claim 8, wherein intra_subpartitions_split_flag is assumed to be equal to 1 otherwise (if cbWidth is greater than MaxTbSizeY). The size of the chroma conversion block follows the following rules:
if the chroma format is equal to 4:4:4, the size of the chroma conversion block is equal to the size of the luma coding block;
otherwise, the size of the chroma conversion block is determined as a function of the size of the luma coding block and the chroma format;
10. The apparatus according to claim 9, wherein the apparatus is determined according to: The ISP information is indicated by IntraSubPartitionsSplitType; and
9. The apparatus of claim 8, wherein ISP is used to split the luma coding blocks of the coding unit if IntraSubPartitionsSplitType != ISP_NO_SPLIT. A non-transitory computer-readable storage medium storing instructions, the instructions, when executed by a processing circuit, causing the processing circuit to:
Obtaining intra sub-partition (ISP) information based on flags in a bitstream, the flags including at least one of a mode flag or a split flag, the mode flag comprising: indicates whether the coding unit is partitioned into rectangular transform block subpartitions, the partition flag indicates whether the intra subpartition (ISP) partition type is horizontal or vertical; the ISP information indicates whether an ISP is used to divide luma coding blocks of a coding unit;
determining the size of a chroma transform block (TB) of the coding unit based on SubWidthC and SubHeightC, where SubWidthC and SubHeightC are variables dependent on chroma format information, if at least a first condition is satisfied; and the chroma format information indicates a chroma format of a picture to which the coding unit belongs, and the chroma format is 4:2:0, 4:2:2, or 4:4:4. and the first condition is: 1) a single tree is used to partition the coding unit, and 2) the ISP information is used for the luma coding. - a step including indicating that the ISP is used to divide the block;
A storage medium that executes. 16. The non-transitory computer-readable storage medium of claim 15, wherein the size of the chroma conversion block also depends on the size of the luma coding block. The size of the chroma conversion block is:
wC = CbWidth[x0][y0] / SubWidthC; and
hC = CbHeight[x0][y0] / SubHeightC;
, wC represents the width of the chroma conversion block, hC represents the height of the chroma conversion block, CbWidth represents the width of the luma coding block, and CbHeight represents the height of the luma coding block. 17. The non-transitory computer-readable storage medium of claim 16, representing: the mode flag is intra_subpartitions_mode_flag;
intra_subpartitions_mode_flag equal to 1 indicates that the current intra coding unit is partitioned into NumIntraSubPartitions rectangular transform block subpartitions;
intra_subpartitions_mode_flag equal to 0 indicates that the current intra coding unit is not partitioned into rectangular transform block subpartitions;
16. The non-transitory computer-readable storage medium of claim 15, wherein intra_subpartitions_mode_flag is presumed to be equal to 0 if absent. The split flag is intra_subpartitions_split_flag;
If intra_subpartitions_split_flag does not exist:
If cbHeight is greater than MaxTbSizeY, intra_subpartitions_split_flag is assumed to be equal to 0;
16. The non-transitory computer-readable storage medium of claim 15, wherein intra_subpartitions_split_flag is assumed to be equal to 1 otherwise (if cbWidth is greater than MaxTbSizeY). The ISP information is indicated by IntraSubPartitionsSplitType; and
16. The non-transitory computer-readable storage medium of claim 15, wherein ISP is used to split the luma coding blocks of the coding unit if IntraSubPartitionsSplitType != ISP_NO_SPLIT.

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